Abel Kirui performed a little shimmy in his chair Friday at the Chicago Marathon race headquarters, demonstrating what he has in store if he wins Sunday morning.

Kirui danced last year at Grant Park when he completed the course in 2 hours, 11 minutes, 23 seconds for the victory.

"If I win, I will do an amazing dance," Kirui said with a smile.

Kirui, from Kenya, will attempt to be the first men's marathoner to repeat here since Sammy Wanjiru in 2009-10.

Florence Kiplagat, from Kenya, is hoping to become the first three-peat champion in the women's field. She set an aggressive pace and won last year in 2:21:32, and won the 2015 marathon in 2:23:33.

"Three years in a row would mean a lot," said Kiplagat, a mother of two who owns and operates a service station and runs 200 kilometers (about 124 miles) per week in training. "It would mean I'm a real champion, a fighter."

Kirui and Kiplagat will have stiff challenges at this year's race — the 40th anniversary of the event.

Tirunesh Dibaba, from Ethiopia, is considered a strong contender against Kiplagat.

Dibaba became the third fastest marathoner of all time in London when she finished second in 2:17:56. Some wonder if she could break Paula Radcliffe's 2002 [CQ]course record here (2:17:18) when she competes Sunday in just her third marathon.

"I want to improve my personal record," said Dibaba, a renowned track star who was speaking through an interpreter. "One of the things I love is running fast times. I want to run a good time here. This is my third marathon and I would really love to win here."

With the 40th Chicago Marathon set for Sunday, we take a look back at the history of the race.

Kiplagat, who placed ninth in the London marathon in April in 2:26:25, said she is not thinking about her competition.

"I don't put myself under pressure," she said. "I (focus on) myself. I don't race against someone else. I race against myself to win. You don't put it in your mind. It's just you."

Kirui has some challengers in world record holder Dennis Kimetto, Stanley Biwott and Feyisa Lilesa. But said he senses a repeat.

"To be No. 1 sometimes is easy but to maintain it can be difficult," he said. "But if I can make it two times (as) No. 1 … my training is good and telling me something good is ahead."

In the wheelchair marathon, Marcel Hug is hoping to defend his men's title after edging out previous Chicago champion Kurt Fearnley in 1:32:57.

After taking off about three months to contend with blood clots, Tatyana McFadden will go for her seventh straight title in the women's wheelchair marathon. McFadden, who trains with the University of Illinois club, won last year's race in 1:42:28 and set the course record in 2015 in 1:41:10.

"I've been so healthy all these years," she said. "It has been really hard to sit out on some races and take a step back to focus on training and my health and recovery. It has been a long time coming. I'm ready to compete again."